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Wednesday, July 23, 2014

The 27 Foot Long Speaker

Audiophiles can be quite obsessive, and when you're an engineer it can make that obsession even worse. In the 1930s engineer Roderick Denman built a huge loudspeaker into the roof of his house that faced straight downward into an octagonal listening area that he used for the flare of his giant horn, which extended some 20 feet. There he placed a few reclining chairs. Basically, you were sitting entirely inside the speaker when you listened!

In order to get the best frequency response from the horn, it had to be large and straight. Many horns of the day were curved, which provided great low end response, but limited the highs, which why the only way Denman could could achieve such a large horn was to build it as part of his house.

The Western Electric 555W

The compression driver used to drive the horn was the then new Western Electric 555W, designed by the famous Bell Labs and said to be one of the greatest speakers ever made. They have run in theaters for more than 60 years and today are bought and sold for thousands of dollars.

The horn was used for demonstrations until a wall fell on it during WWII and it was almost destroyed. Since then it's been part of the Scientific Museum at Blythe House in the UK, but it wasn't until recently that sound artist in residence Alex Kolkowski decided to build a modern version of it according to the original specification.

After 8 months the speaker is finally operational and on display at the museum. It's also working again with the help of the original driver, and has a frequency response of 32Hz to 6kHz.

It's 27 feet long!

Those of us who grew up with horn-loaded speakers know how good they can sound under the right circumstances. They're very efficient and directional, which is great for live sound, but also pretty bulky, which is why line-arrays are used in virtually every sound reinforcement situation today. Too bad, because they sounded great.

That said, it's very cool that Denman's horn has been recreated and available for all to see and hear again.